Catalinbread - Naga Viper

mysticwhiskey · Post by **mysticwhiskey** » 25 Sep 2011, 02:28

I could be wrong, but your 'Heat' pot looks to be wired backwards. At minimum rotation, your heat pot presents a resistance of 0 ohms. The pot on the vero and pcb layouts has a resistance of 1Kohm at minimum rotation. When I did the PCB layout I checked the photos that jwpartain had posted, and you can see the heat pot has pins 1 and connected together, going to the 47u cap.

coldcraft · Post by **coldcraft** » 25 Sep 2011, 02:32

i'm sorry, i thought we were talking about the boost control.

the boost pot is linear so we can swap it, as long as 2 is tied to either 3 or 1.

Heat pot is log, so it must go in the correct way. however, if it happens to sound as if the taper is weird, you just need to swap the 2nd lug to the other arrangement.

I can't offer any layout review at this time, I've never really worked with vero before.

jimmybjj · Post by **jimmybjj** » 25 Sep 2011, 02:55

Pot numbers are backwards in the layout diagram, but everything is correct. Any of you eagle experts know how to change the pot numbers with out having to change the layout? board can be pot mounted and fit in a 1590b

Layout

jimmybjj · Post by **jimmybjj** » 25 Sep 2011, 04:34

layout updated and correct.

okgb · Post by **okgb** » 25 Sep 2011, 06:38

Really it's easy enough to just follow the schematic and make a literal translation
that's how i did my ptp with so few parts , no problem , nothing crossing over or jumpers
nice board though
and aren't both pots linear B with just the range being log ?

ezs · Post by **ezs** » 25 Sep 2011, 09:15

Does Heat look correct now?

okgb · Post by **okgb** » 26 Sep 2011, 13:28

The input needs to go directly to the board first , at the very least ,
I did mine with the three caps connected at the input point then .68 to the range pot

I don't think it matters ? maybe easier to wire but using the vero sideways like that
makes it easier to copy the schematic think of it as rails for input , ground , pwr

roseblood11 · Post by **roseblood11** » 26 Sep 2011, 15:45

The 2n2222 is a very noisy part, it's used in the LofoMofo only because of that reason... Wouldn't it be better to use a low noise transistor with low hfe? Maybe BC549A or s.th. similar?

ezs · Post by **ezs** » 26 Sep 2011, 17:45

okgb wrote:The input needs to go directly to the board first , at the very least ,
I did mine with the three caps connected at the input point then .68 to the range pot

I don't think it matters ? maybe easier to wire but using the vero sideways like that
makes it easier to copy the schematic think of it as rails for input , ground , pwr

Input should be good? Ill try it out in a few, kinda swamped with gear. Will post results, Thanks guys.

okgb · Post by **okgb** » 26 Sep 2011, 17:51

maybe it just looks odd input going to the pot first , i'd still make it go to the board
and caps so it's always there , then jump off to the pot

coldcraft · Post by **coldcraft** » 27 Sep 2011, 14:47

roseblood11 wrote:The 2n2222 is a very noisy part, it's used in the LofoMofo only because of that reason... Wouldn't it be better to use a low noise transistor with low hfe? Maybe BC549A or s.th. similar?

I thought it was supposed to use 2n222, which is germanium...

roseblood11 · Post by **roseblood11** » 27 Sep 2011, 17:11

coldcraft wrote:
roseblood11 wrote:The 2n2222 is a very noisy part, it's used in the LofoMofo only because of that reason... Wouldn't it be better to use a low noise transistor with low hfe? Maybe BC549A or s.th. similar?

I thought it was supposed to use 2n222, which is germanium...

The picture is very clear: 2n2222a, in a to-92 case = npn silicon

HEAD · Post by **HEAD** » 27 Sep 2011, 17:29

roseblood11 wrote:
coldcraft wrote:
roseblood11 wrote:The 2n2222 is a very noisy part, it's used in the LofoMofo only because of that reason... Wouldn't it be better to use a low noise transistor with low hfe? Maybe BC549A or s.th. similar?

I thought it was supposed to use 2n222, which is germanium...

The picture is very clear: 2n2222a, in a to-92 case = npn silicon

It is a P2N2222A to be exactly. Which does make a difference - though most probably only in the pinout configuration. P2N2222A pinout is different from a PN2222A and as far as I know 2N2222A only appears in a TO-18 case.

okgb · Post by **okgb** » 27 Sep 2011, 21:14

Curious , i bought some 2N2222A to-18 Transistors for a mic preamp and they were specifically
marked audio , the few that i'm looking at now are marked NPN switching transistor
I was just glad i happened to have the one called for , but maybe something else will Sound better ?

okgb · Post by **okgb** » 01 Oct 2011, 14:30

Naive question , Is there a germanium transistor i can sub in ?
reversing the psu & diode would be easy

roseblood11 · Post by **roseblood11** » 01 Oct 2011, 16:01

Why would you do that? Do you like more hiss?
If you really want to do that, you might have to change some values, if the transistor has less gain. Have a look at the pdf about the "Austin Treble Booster" at geofex.com.

okgb · Post by **okgb** » 01 Oct 2011, 17:43

It may be the circuit and not the transistor but some of the ones I've heard
seem to have a slight squishy / compressed quality which i like .
That's why i'd want to do that , but i may be mistaken ,
the viper as I've built it , so far is not a keeper

okgb · Post by **okgb** » 02 Oct 2011, 13:00

I see some of this discussion is covered on the red rooster thread
[ never knew what that was -til i looked ]
viewtopic.php?f=7&t=4178

ezs · Post by **ezs** » 11 Nov 2011, 04:48

: Naga Viper-2 EZS.gif (20.04 KiB) Viewed 2338 times

ezs wrote:
okgb wrote:The input needs to go directly to the board first , at the very least ,
I did mine with the three caps connected at the input point then .68 to the range pot

I don't think it matters ? maybe easier to wire but using the vero sideways like that
makes it easier to copy the schematic think of it as rails for input , ground , pwr
Input should be good? Ill try it out in a few, kinda swamped with gear. Will post results, Thanks guys.

I finally made it, heres the vero I used. Its pretty cool but I cant seem to notice the gain much. On my build its very very subtle. I a/b 'd it against the Brain Seltzer and its way better imo. Tested through a Mesa Nomad 45 clean channel, and it gives the right amount of push. Range knob is a hit.

ezs · Post by **ezs** » 11 Nov 2011, 06:18

I just happen to have the (ON p2n2222a). The gain is more noticeable when the boost is backed off. Just a learning curve as Im playing this thing. Like it lots. I tried a 2n5088 and felt it was too bright. The 2n2222a has a more playable feel and tone.

Catalinbread - Naga Viper [traced]